Multiple Sclerosis (MS) is a demyelinating disease in which excessive immunoglobulin (Ig) production takes place within the central nervous system. Previous work has shown that an imbalance in T-cell subpopulations is associated with this abnormality. It is possible that (a) the excessive Ig production per se is not relevant, and that only the recently described anti-oligodendrocyte (ODC) antibodies are significant, (b) the imbalance in T cells is a consequence of this primary disorder, implying that changes in antigen-specific and/or non-antigen-specific suppressor T cells are only secondary. The use of hetero- and alloantisera against human-T cell subsets will help to better analyze T cell subsets abnormalities in MS. The ability of the patient's B cells to produce more Ig's and, more specifically, anti-ODC antibodies in vitro will be tested, using bovine and monkey ODC as well an established human oligodendroglioma cell line. The ability of normal and MS T cells and T-cell subsets to influence the production of both Ig and anti-ODC antibodies in vitro will be tested. This should help to determine whether the anti-OCD production can be controlled by normal T cells or MS T cells after in-vitro immunemanipulation. This would increase our understanding of MS and, possibly, open a way toward an effective therapeutic approach to the disease.